scope:

Quantum key distribution (QKD) comprises technologies that use quantum mechanical effects to distribute private keys to distant partners. The goals of the present document are as follows:

• to make precise the nature of the security claim, including its statistical component;

• to list meaningful restrictions of adversarial action;

• to clarify the difference between security claim of a protocol (based on models) and the security claim of its implementation;

• to carefully list all the usual components of a QKD protocol with their critical characterizations.

The present document is developed by the QKD ISG group in which participate experts of QKD theory and practice. With the goals identified above, the present document shall help to:

• clarify the role QKD devices can play in a security infrastructure given the exact nature of their security claim;

• classify QKD devices regarding the security level they can achieve;

• clarify which parameters need to be monitored continuously or periodically to assure the generation of a secret key for the different security levels.

On the other hand, the present document will not try to do the following:

• to give specific parameters for successful QKD as these numbers change with time;

• to endorse particular security proofs.